CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Unidad Ejecutora - UE
Crystal Structure and Characterisation of Mercury(II) Dichromate
M.WEIL; STÖGER, B.; E.ZOBETZ; ENRIQUE JOSE BARAN
Monatshefte Für Chemie (Vienna)
Lugar: Viena, Austria; Año: 2006 vol. 137 p. 987 - 987
Dark-red crystals of HgCr2O7 were grown by reaction of HgO and CrO3 in excess at 200 ºC for four days. The crysytal structure was determined by single crystal X-ray diffractometry. The compound belongs to the trigonal crystal system, space group P3(2) and Z = 3. It consists of nearly linear HgO2 units and dichromate units linked into infinite chains O3Cr-O-CrO3-Hg-O3Cr-O-CrO3 running parallel to the c-axis. The dichromate anion exhibits a staggered conformation with a bent Cr-O-Cr bridging angle of 140.7(6) º. Upon heating above 300 ºC, HgCr2O7 decomposes in a two-step mechanism to Cr2O3. The compound was additionally characterized by vibrational (IR and Raman) spectroscopy.